Relationships between recruits of abalone Haliotis midae, encrusting corallines and the sea urchin Parechinus angulosus

In kelp beds of the South-Western Cape. South Africa, a strong positive rel ationship exists between the sea urchin Parechinus angulosus and juveniles of the abalone Haliotis midae. Field surveys reported here revealed a posit ive, but weak, association between this urchin and H. midae recruits (i.e. individuals <3 mm shell length). Selectivity indices showed that recruits o ccurred exclusively on encrusting coralline algae and showed preferences fo r strongly textured corallines. rather than those with smooth texture. On s mooth corallines, around 80% of recruits were under urchins, compared with about 25% on textured corallines, suggesting that any need for shelter bene ath urchins is greatest on smooth surfaces.